Display screen or portion thereof with a graphical user interface



The FIGURE is a front view of a display screen or portion thereof with agraphical user interface.

The outermost broken lines illustrate a display screen or portionthereof and form no part of the claimed design. The remaining brokenlines, illustrating portions of the graphical user interface, form nopart of the claimed design.

CLAIM The ornamental design for a display screen or portion thereof with a graphical user interface, as shown and described. 